Several users have reported an issue in which battery drains faster after installing the new iOS 7 update. It is important to note that battery drain seems to be a constant complaint with every new iOS update. If you are experiencing short battery life problems, follow these tips and tricks for better iPhone/iPad battery life.
Restart/reset your device. Simply restarting your device may solve your problem. To restart your device, press and hold the power (Sleep/Wake) button until you see the red slider then slide the slider.Then press and hold the Sleep/Wake button until you see the Apple logo. If restarting does not help, you may also want to reset your device by simple pressing and holding the home button and the Sleep/Wake button together until you see the Apple logo.
Power cycle. Completely drain your battery, drain it until it shuts down on its own. Then charge it back up to full.Do this once a month.
Reset All Settings. Important: Note that this option will not delete any of your media or data but you will lose some of your saved data, like game levels etc. To do this, tap Settings > General > Reset > Reset All settings.
Restore your device as new. Tap Settings > General > Reset > Erase All Content and Settings. Note that this will setting will remove all data and media on your iOS device. Once the iPhone or iPad (or iPod touch) reboots select “Set Up as New”. Later, you may use iCloud/iTunes to restore your device from your backups.
Turn off what you are not using
Turn off AirDrop when not using it (Control Center).
Turn off Background App Refresh (Settings > General > Background App Refresh).
Turn off Location Services (Settings > Privacy > Location Services).
Turn off Push Notifications and Mail (Settings > Mail, Contacts, Calendars > Push then Settings > Notification Center and tap each app then turn the Notification Center toggle to OFF).
Turn down the screen brightness (turn off Auto-Brightness) (Settings > Wallpapers & Brightness).
Turn off Bluetooth when not using it (Settings > Bluetooth).
Turn off Wi-Fi when not using it (Settings > Wi-Fi).
Turn off LTE when not using it (Settings > General > Cellular).
Disable Siri when not using it (Settings > General > Siri).
Disable Time Zone Adjustment (Settings > Privacy > Location Services > System Services > Setting Time Zone).